sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory

[jijianwen]

When I followed instructions on README to create a HA Kubernetes cluster with two worker nodes and OVN-Kubernetes in Raft mode as a CNI, I got errors as below by running 'ansible-playbook -i inventory/vms.local.generated playbooks/kube-install-ovn.yml':

TASK [cri-o-install : set fs.may_detach_mounts] *******************************************************************
fatal: [kube-master2]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory\n"}
fatal: [kube-node-2]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory\n"}
fatal: [kube-master1]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory\n"}
fatal: [kube-node-1]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory\n"}
fatal: [kube-master3]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/fs/may_detach_mounts: No such file or directory\n"}

I logged in kube-master1, found the running kernel is 5.13.12-1.el7.elrepo.x86_64. It seems fs.may_detach_mounts is not available on that kernel but available on 3.10.0-957.27.2.el7.x86_64.